It is highly unlikely you are the worst mouth the dentist has ever seen. But, if you are, so what? The dentist is there to assess your mouth and give you options to get healthier. They are not there to judge you and make you feel bad.
Dentists have seen lots of mouths and heard the accompanying stories. We know and understand how people can get off track with their health.
You are human. Be kind to yourself and just begin the journey towards being healthier.
Chose a dentist that you are comfortable with and who will walk next to you and encourage you on your journey to health.